1. Field of the Invention
The present invention relates to a touch sensor system and a multiplexer thereof, and more particularly, to a multiplexer capable of reducing a pin number of a touch controller in the touch sensor system.
2. Description of the Prior Art
In recent years, the touch sensing technology advances rapidly, and many consumer electronic products such as mobile phones, GPS navigator systems, tablets, personal digital assistants (PDA) and laptops are equipped with touch sensing functions. A conventional touch sensor system is composed of a touch panel and a touch integrated circuit (IC). The touch IC is capable of transmitting driving signals to the touch panel and correspondingly receiving sensing signals from touch sensing areas on the touch panel.
Please refer to FIG. 1, which is a schematic diagram of a general touch sensor system 10. As shown in FIG. 1, the touch sensor system 10 includes a touch panel 100 and a touch IC 102. The touch panel 100 includes 9 touch sensing areas arranged in a 3×3 array. Each touch sensing area is connected to the touch IC 102 via a connecting wire and a contact. In such a situation, the touch IC 102 should include at least 9 I/O pins for connecting with the touch sensing areas.
However, as the commercial requirements of larger touch panels increase, the number of touch sensing areas on a touch panel increases with the size of the touch panel. To date, there may be hundreds or thousands of touch sensing areas on a touch panel. For example, in a touch panel having touch sensing areas arranged in a 32×18 array, there are 576 touch sensing areas on the touch panel. In such a situation, the touch IC should include at least 576 I/O pins for connecting with the touch sensing areas. The large number of I/O pins significantly increases the die size of the touch IC, and thus increases the cost. The wire bonding quality is also reduced since the bonding pitch is limited. Thus, there is a need for improvement over the prior art.